feat: add stats endpoint for inscription counts

migrations/1683909884000_inscriptions_per_block.ts

@@ -0,0 +1,25 @@
+/* eslint-disable @typescript-eslint/naming-convention */
+import { MigrationBuilder, ColumnDefinitions } from 'node-pg-migrate';
+
+export const shorthands: ColumnDefinitions | undefined = undefined;
+
+export function up(pgm: MigrationBuilder): void {
+  pgm.createTable('inscriptions_per_block', {
+    block_height: {
+      type: 'int',
+      primaryKey: true,
+    },
+    inscriptions: {
+      type: 'int',
+      notNull: true,
+    },
+    inscriptions_total: {
+      type: 'int',
+      notNull: true,
+    },
+  });
+}
+
+export function down(pgm: MigrationBuilder): void {
+  pgm.dropTable('inscriptions_per_block');
+}

src/api/routes/stats.ts

@@ -0,0 +1,25 @@
+import { TypeBoxTypeProvider } from '@fastify/type-provider-typebox';
+import { FastifyPluginAsync, FastifyPluginCallback } from 'fastify';
+import { Server } from 'http';
+
+const IndexRoutes: FastifyPluginCallback<Record<never, never>, Server, TypeBoxTypeProvider> = (
+  fastify,
+  options,
+  done
+) => {
+  fastify.get('/stats/inscriptions', async (request, reply) => {
+    const inscriptions = await fastify.db.getInscriptionCountPerBlock();
+    await reply.send({
+      results: inscriptions,
+    });
+  });
+  done();
+};
+
+export const StatsRoutes: FastifyPluginAsync<
+  Record<never, never>,
+  Server,
+  TypeBoxTypeProvider
+> = async fastify => {
+  await fastify.register(IndexRoutes);
+};

src/pg/pg-store.ts

@@ -11,6 +11,7 @@ import { BasePgStore } from './postgres-tools/base-pg-store';
 import {
   DbFullyLocatedInscriptionResult,
   DbInscriptionContent,
+  DbInscriptionCountPerBlock,
   DbInscriptionIndexFilters,
   DbInscriptionIndexOrder,
   DbInscriptionIndexPaging,
@@ -77,6 +78,9 @@ export class PgStore extends BasePgStore {
             }
           }
         }
+        const block_height = event.block_identifier.index;
+        await this.rollBackInscriptionCount({ block_height });
+        logger.info(`PgStore rollback inscription counts for block ${block_height}`);
       }
       for (const event of payload.apply) {
         const block_hash = normalizedHexString(event.block_identifier.hash);
@@ -130,10 +134,8 @@ export class PgStore extends BasePgStore {
                   block_height: event.block_identifier.index,
                   address: transfer.updated_address,
                   output: output,
-                  offset: offset ?? null,
-                  value: transfer.post_transfer_output_value
-                    ? transfer.post_transfer_output_value.toString()
-                    : null,
+                  offset: offset,
+                  value: transfer.post_transfer_output_value?.toString() ?? null,
                   timestamp: event.timestamp,
                   sat_ordinal: transfer.ordinal_number.toString(),
                   sat_rarity: satoshi.rarity,
@@ -147,6 +149,9 @@ export class PgStore extends BasePgStore {
             }
           }
         }
+        const block_height = event.block_identifier.index;
+        await this.insertInscriptionCount({ block_height });
+        logger.info(`PgStore apply inscription counts at block ${block_height}`);
       }
     });
     await this.normalizeInscriptionLocations({ inscription_id: Array.from(updatedInscriptionIds) });
@@ -474,6 +479,10 @@ export class PgStore extends BasePgStore {
     }
   }
 
+  async getInscriptionCountPerBlock(): Promise<DbInscriptionCountPerBlock[]> {
+    return this.sql<DbInscriptionCountPerBlock[]>`SELECT * FROM inscriptions_per_block`;
+  }
+
   async refreshMaterializedView(viewName: string) {
     const isProd = process.env.NODE_ENV === 'production';
     await this.sql`REFRESH MATERIALIZED VIEW ${
@@ -621,6 +630,32 @@ export class PgStore extends BasePgStore {
     return inscription_id;
   }
 
+  private async insertInscriptionCount(args: { block_height: number }): Promise<void> {
+    await this.sql`
+      WITH previous AS (
+        SELECT COALESCE(p.inscriptions_total, 0) as previous_total
+        FROM inscriptions_per_block p
+        WHERE p.block_height = ${args.block_height - 1}
+        LIMIT 1
+      ), current AS (
+        SELECT block_height, COUNT(*) as inscriptions, COUNT(*) + (SELECT previous_total FROM previous) as inscriptions_total
+        FROM locations
+        WHERE block_height = ${args.block_height} AND genesis = true
+        GROUP BY block_height
+        LIMIT 1
+      )
+      INSERT INTO inscriptions_per_block
+      SELECT * FROM current
+      ON CONFLICT (block_height) DO UPDATE SET
+        inscriptions = EXCLUDED.inscriptions,
+        inscriptions_total = EXCLUDED.inscriptions_total;
+    `;
+  }
+
+  private async rollBackInscriptionCount(args: { block_height: number }): Promise<void> {
+    await this.sql`DELETE FROM inscriptions_per_block WHERE block_height = ${args.block_height}`;
+  }
+
   private async rollBackInscriptionGenesis(args: { genesis_id: string }): Promise<void> {
     // This will cascade into dependent tables.
     await this.sql`DELETE FROM inscriptions WHERE genesis_id = ${args.genesis_id}`;

src/pg/types.ts

@@ -212,3 +212,9 @@ export enum DbInscriptionIndexResultCountType {
   /** Filtered by custom arguments */
   custom,
 }
+
+export type DbInscriptionCountPerBlock = {
+  block_height: number;
+  inscriptions: number;
+  inscriptions_total: number;
+};